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Subject[PATCH v2 1/1] KVM: make pid available for uevents without debugfs
Date
Simplify and improve the code so that the PID is always available in
the uevent even when debugfs is not available.

This adds a userspace_pid field to struct kvm, as per Radim's
suggestion, so that the PID can be retrieved on destruction too.

Acked-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Fixes: 286de8f6ac9202 ("KVM: trigger uevents when creating or destroying a VM")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
---
include/linux/kvm_host.h | 1 +
virt/kvm/kvm_main.c | 35 ++++++++++++-----------------------
2 files changed, 13 insertions(+), 23 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 648b34c..890b706 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -445,6 +445,7 @@ struct kvm {
struct kvm_stat_data **debugfs_stat_data;
struct srcu_struct srcu;
struct srcu_struct irq_srcu;
+ pid_t userspace_pid;
};

#define kvm_err(fmt, ...) \
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 82987d4..f3f7427 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3883,7 +3883,6 @@ static const struct file_operations *stat_fops[] = {
static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
{
struct kobj_uevent_env *env;
- char *tmp, *pathbuf = NULL;
unsigned long long created, active;

if (!kvm_dev.this_device || !kvm)
@@ -3907,38 +3906,28 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
add_uevent_var(env, "CREATED=%llu", created);
add_uevent_var(env, "COUNT=%llu", active);

- if (type == KVM_EVENT_CREATE_VM)
+ if (type == KVM_EVENT_CREATE_VM) {
add_uevent_var(env, "EVENT=create");
- else if (type == KVM_EVENT_DESTROY_VM)
+ kvm->userspace_pid = task_pid_nr(current);
+ } else if (type == KVM_EVENT_DESTROY_VM) {
add_uevent_var(env, "EVENT=destroy");
+ }
+ add_uevent_var(env, "PID=%d", kvm->userspace_pid);

if (kvm->debugfs_dentry) {
- char p[ITOA_MAX_LEN];
-
- snprintf(p, sizeof(p), "%s", kvm->debugfs_dentry->d_name.name);
- tmp = strchrnul(p + 1, '-');
- *tmp = '\0';
- add_uevent_var(env, "PID=%s", p);
- pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
- if (pathbuf) {
- /* sizeof counts the final '\0' */
- int len = sizeof("STATS_PATH=") - 1;
- const char *pvar = "STATS_PATH=";
-
- tmp = dentry_path_raw(kvm->debugfs_dentry,
- pathbuf + len,
- PATH_MAX - len);
- if (!IS_ERR(tmp)) {
- memcpy(tmp - len, pvar, len);
- env->envp[env->envp_idx++] = tmp - len;
- }
+ char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL);
+
+ if (p) {
+ tmp = dentry_path_raw(kvm->debugfs_dentry, p, PATH_MAX);
+ if (!IS_ERR(tmp))
+ add_uevent_var(env, "STATS_PATH=%s", tmp);
+ kfree(p);
}
}
/* no need for checks, since we are adding at most only 5 keys */
env->envp[env->envp_idx++] = NULL;
kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp);
kfree(env);
- kfree(pathbuf);
}

static int kvm_init_debug(void)
--
2.7.4
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